1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ALPHA_PGTABLE_H
3 #define _ALPHA_PGTABLE_H
4
5 #include <asm-generic/pgtable-nopud.h>
6
7 /*
8 * This file contains the functions and defines necessary to modify and use
9 * the Alpha page table tree.
10 *
11 * This hopefully works with any standard Alpha page-size, as defined
12 * in <asm/page.h> (currently 8192).
13 */
14 #include <linux/mmzone.h>
15
16 #include <asm/page.h>
17 #include <asm/processor.h> /* For TASK_SIZE */
18 #include <asm/machvec.h>
19 #include <asm/setup.h>
20 #include <linux/page_table_check.h>
21
22 struct mm_struct;
23 struct vm_area_struct;
24
25 /* Certain architectures need to do special things when PTEs
26 * within a page table are directly modified. Thus, the following
27 * hook is made available.
28 */
29 #define set_pte(pteptr, pteval) ((*(pteptr)) = (pteval))
30
31 /* PMD_SHIFT determines the size of the area a second-level page table can map */
32 #define PMD_SHIFT (PAGE_SHIFT + (PAGE_SHIFT-3))
33 #define PMD_SIZE (1UL << PMD_SHIFT)
34 #define PMD_MASK (~(PMD_SIZE-1))
35
36 /* PGDIR_SHIFT determines what a third-level page table entry can map */
37 #define PGDIR_SHIFT (PAGE_SHIFT + 2*(PAGE_SHIFT-3))
38 #define PGDIR_SIZE (1UL << PGDIR_SHIFT)
39 #define PGDIR_MASK (~(PGDIR_SIZE-1))
40
41 /*
42 * Entries per page directory level: the Alpha is three-level, with
43 * all levels having a one-page page table.
44 */
45 #define PTRS_PER_PTE (1UL << (PAGE_SHIFT-3))
46 #define PTRS_PER_PMD (1UL << (PAGE_SHIFT-3))
47 #define PTRS_PER_PGD (1UL << (PAGE_SHIFT-3))
48 #define USER_PTRS_PER_PGD (TASK_SIZE / PGDIR_SIZE)
49
50 /* Number of pointers that fit on a page: this will go away. */
51 #define PTRS_PER_PAGE (1UL << (PAGE_SHIFT-3))
52
53 #ifdef CONFIG_ALPHA_LARGE_VMALLOC
54 #define VMALLOC_START 0xfffffe0000000000
55 #else
56 #define VMALLOC_START (-2*PGDIR_SIZE)
57 #endif
58 #define VMALLOC_END (-PGDIR_SIZE)
59
60 /*
61 * OSF/1 PAL-code-imposed page table bits
62 */
63 #define _PAGE_VALID 0x0001
64 #define _PAGE_FOR 0x0002 /* used for page protection (fault on read) */
65 #define _PAGE_FOW 0x0004 /* used for page protection (fault on write) */
66 #define _PAGE_FOE 0x0008 /* used for page protection (fault on exec) */
67 #define _PAGE_ASM 0x0010
68 #define _PAGE_KRE 0x0100 /* xxx - see below on the "accessed" bit */
69 #define _PAGE_URE 0x0200 /* xxx */
70 #define _PAGE_KWE 0x1000 /* used to do the dirty bit in software */
71 #define _PAGE_UWE 0x2000 /* used to do the dirty bit in software */
72
73 /* .. and these are ours ... */
74 #define _PAGE_DIRTY 0x20000
75 #define _PAGE_ACCESSED 0x40000
76
77 /* We borrow bit 39 to store the exclusive marker in swap PTEs. */
78 #define _PAGE_SWP_EXCLUSIVE 0x8000000000UL
79
80 /*
81 * NOTE! The "accessed" bit isn't necessarily exact: it can be kept exactly
82 * by software (use the KRE/URE/KWE/UWE bits appropriately), but I'll fake it.
83 * Under Linux/AXP, the "accessed" bit just means "read", and I'll just use
84 * the KRE/URE bits to watch for it. That way we don't need to overload the
85 * KWE/UWE bits with both handling dirty and accessed.
86 *
87 * Note that the kernel uses the accessed bit just to check whether to page
88 * out a page or not, so it doesn't have to be exact anyway.
89 */
90
91 #define __DIRTY_BITS (_PAGE_DIRTY | _PAGE_KWE | _PAGE_UWE)
92 #define __ACCESS_BITS (_PAGE_ACCESSED | _PAGE_KRE | _PAGE_URE)
93
94 #define _PFN_MASK 0xFFFFFFFF00000000UL
95
96 #define _PAGE_TABLE (_PAGE_VALID | __DIRTY_BITS | __ACCESS_BITS)
97 #define _PAGE_CHG_MASK (_PFN_MASK | __DIRTY_BITS | __ACCESS_BITS)
98
99 /*
100 * All the normal masks have the "page accessed" bits on, as any time they are used,
101 * the page is accessed. They are cleared only by the page-out routines
102 */
103 #define PAGE_NONE __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOR | _PAGE_FOW | _PAGE_FOE)
104 #define PAGE_SHARED __pgprot(_PAGE_VALID | __ACCESS_BITS)
105 #define PAGE_COPY __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOW)
106 #define PAGE_READONLY __pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOW)
107 #define PAGE_KERNEL __pgprot(_PAGE_VALID | _PAGE_ASM | _PAGE_KRE | _PAGE_KWE)
108
109 #define _PAGE_NORMAL(x) __pgprot(_PAGE_VALID | __ACCESS_BITS | (x))
110
111 #define _PAGE_P(x) _PAGE_NORMAL((x) | _PAGE_FOW)
112 #define _PAGE_S(x) _PAGE_NORMAL(x)
113
114 /*
115 * The hardware can handle write-only mappings, but as the Alpha
116 * architecture does byte-wide writes with a read-modify-write
117 * sequence, it's not practical to have write-without-read privs.
118 * Thus the "-w- -> rw-" and "-wx -> rwx" mapping here (and in
119 * arch/alpha/mm/fault.c)
120 */
121 /* xwr */
122
123 /*
124 * pgprot_noncached() is only for infiniband pci support, and a real
125 * implementation for RAM would be more complicated.
126 */
127 #define pgprot_noncached(prot) (prot)
128
129 /*
130 * ZERO_PAGE is a global shared page that is always zero: used
131 * for zero-mapped memory areas etc..
132 */
133 #define ZERO_PAGE(vaddr) (virt_to_page(ZERO_PGE))
134
135 /*
136 * On certain platforms whose physical address space can overlap KSEG,
137 * namely EV6 and above, we must re-twiddle the physaddr to restore the
138 * correct high-order bits.
139 *
140 * This is extremely confusing until you realize that this is actually
141 * just working around a userspace bug. The X server was intending to
142 * provide the physical address but instead provided the KSEG address.
143 * Or tried to, except it's not representable.
144 *
145 * On Tsunami there's nothing meaningful at 0x40000000000, so this is
146 * a safe thing to do. Come the first core logic that does put something
147 * in this area -- memory or whathaveyou -- then this hack will have
148 * to go away. So be prepared!
149 */
150
151 #if defined(CONFIG_ALPHA_GENERIC) && defined(USE_48_BIT_KSEG)
152 #error "EV6-only feature in a generic kernel"
153 #endif
154 #if defined(CONFIG_ALPHA_GENERIC) || \
155 (defined(CONFIG_ALPHA_EV6) && !defined(USE_48_BIT_KSEG))
156 #define KSEG_PFN (0xc0000000000UL >> PAGE_SHIFT)
157 #define PHYS_TWIDDLE(pfn) \
158 ((((pfn) & KSEG_PFN) == (0x40000000000UL >> PAGE_SHIFT)) \
159 ? ((pfn) ^= KSEG_PFN) : (pfn))
160 #else
161 #define PHYS_TWIDDLE(pfn) (pfn)
162 #endif
163
164 /*
165 * Conversion functions: convert a page and protection to a page entry,
166 * and a page entry and page directory to the page they refer to.
167 */
168 #define page_to_pa(page) (page_to_pfn(page) << PAGE_SHIFT)
169 #define PFN_PTE_SHIFT 32
170 #define pte_pfn(pte) (pte_val(pte) >> PFN_PTE_SHIFT)
171
172 #define pte_page(pte) pfn_to_page(pte_pfn(pte))
173
pfn_pte(unsigned long physpfn,pgprot_t pgprot)174 extern inline pte_t pfn_pte(unsigned long physpfn, pgprot_t pgprot)
175 { pte_t pte; pte_val(pte) = (PHYS_TWIDDLE(physpfn) << 32) | pgprot_val(pgprot); return pte; }
176
pte_modify(pte_t pte,pgprot_t newprot)177 extern inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
178 { pte_val(pte) = (pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot); return pte; }
179
pmd_set(pmd_t * pmdp,pte_t * ptep)180 extern inline void pmd_set(pmd_t * pmdp, pte_t * ptep)
181 { pmd_val(*pmdp) = _PAGE_TABLE | ((((unsigned long) ptep) - PAGE_OFFSET) << (32-PAGE_SHIFT)); }
182
pud_set(pud_t * pudp,pmd_t * pmdp)183 extern inline void pud_set(pud_t * pudp, pmd_t * pmdp)
184 { pud_val(*pudp) = _PAGE_TABLE | ((((unsigned long) pmdp) - PAGE_OFFSET) << (32-PAGE_SHIFT)); }
185
186
187 extern void migrate_flush_tlb_page(struct vm_area_struct *vma,
188 unsigned long addr);
189
190 extern inline unsigned long
pmd_page_vaddr(pmd_t pmd)191 pmd_page_vaddr(pmd_t pmd)
192 {
193 return ((pmd_val(pmd) & _PFN_MASK) >> (32-PAGE_SHIFT)) + PAGE_OFFSET;
194 }
195
196 #define pmd_pfn(pmd) (pmd_val(pmd) >> 32)
197 #define pmd_page(pmd) (pfn_to_page(pmd_val(pmd) >> 32))
198 #define pud_page(pud) (pfn_to_page(pud_val(pud) >> 32))
199
pud_pgtable(pud_t pgd)200 extern inline pmd_t *pud_pgtable(pud_t pgd)
201 {
202 return (pmd_t *)(PAGE_OFFSET + ((pud_val(pgd) & _PFN_MASK) >> (32-PAGE_SHIFT)));
203 }
204
pte_none(pte_t pte)205 extern inline int pte_none(pte_t pte) { return !pte_val(pte); }
pte_present(pte_t pte)206 extern inline int pte_present(pte_t pte) { return pte_val(pte) & _PAGE_VALID; }
pte_clear(struct mm_struct * mm,unsigned long addr,pte_t * ptep)207 extern inline void pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
208 {
209 WRITE_ONCE(pte_val(*ptep), 0);
210 }
211
pmd_none(pmd_t pmd)212 extern inline int pmd_none(pmd_t pmd) { return !pmd_val(pmd); }
pmd_bad(pmd_t pmd)213 extern inline int pmd_bad(pmd_t pmd) { return (pmd_val(pmd) & ~_PFN_MASK) != _PAGE_TABLE; }
pmd_present(pmd_t pmd)214 extern inline int pmd_present(pmd_t pmd) { return pmd_val(pmd) & _PAGE_VALID; }
pmd_clear(pmd_t * pmdp)215 extern inline void pmd_clear(pmd_t * pmdp) { pmd_val(*pmdp) = 0; }
216
pud_none(pud_t pud)217 extern inline int pud_none(pud_t pud) { return !pud_val(pud); }
pud_bad(pud_t pud)218 extern inline int pud_bad(pud_t pud) { return (pud_val(pud) & ~_PFN_MASK) != _PAGE_TABLE; }
pud_present(pud_t pud)219 extern inline int pud_present(pud_t pud) { return pud_val(pud) & _PAGE_VALID; }
pud_clear(pud_t * pudp)220 extern inline void pud_clear(pud_t * pudp) { pud_val(*pudp) = 0; }
221
222 /*
223 * The following only work if pte_present() is true.
224 * Undefined behaviour if not..
225 */
pte_write(pte_t pte)226 extern inline int pte_write(pte_t pte) { return !(pte_val(pte) & _PAGE_FOW); }
pte_dirty(pte_t pte)227 extern inline int pte_dirty(pte_t pte) { return pte_val(pte) & _PAGE_DIRTY; }
pte_young(pte_t pte)228 extern inline int pte_young(pte_t pte) { return pte_val(pte) & _PAGE_ACCESSED; }
229
pte_wrprotect(pte_t pte)230 extern inline pte_t pte_wrprotect(pte_t pte) { pte_val(pte) |= _PAGE_FOW; return pte; }
pte_mkclean(pte_t pte)231 extern inline pte_t pte_mkclean(pte_t pte) { pte_val(pte) &= ~(__DIRTY_BITS); return pte; }
pte_mkold(pte_t pte)232 extern inline pte_t pte_mkold(pte_t pte) { pte_val(pte) &= ~(__ACCESS_BITS); return pte; }
pte_mkwrite_novma(pte_t pte)233 extern inline pte_t pte_mkwrite_novma(pte_t pte){ pte_val(pte) &= ~_PAGE_FOW; return pte; }
pte_mkdirty(pte_t pte)234 extern inline pte_t pte_mkdirty(pte_t pte) { pte_val(pte) |= __DIRTY_BITS; return pte; }
pte_mkyoung(pte_t pte)235 extern inline pte_t pte_mkyoung(pte_t pte) { pte_val(pte) |= __ACCESS_BITS; return pte; }
236
237 /*
238 * The smp_rmb() in the following functions are required to order the load of
239 * *dir (the pointer in the top level page table) with any subsequent load of
240 * the returned pmd_t *ret (ret is data dependent on *dir).
241 *
242 * If this ordering is not enforced, the CPU might load an older value of
243 * *ret, which may be uninitialized data. See mm/memory.c:__pte_alloc for
244 * more details.
245 *
246 * Note that we never change the mm->pgd pointer after the task is running, so
247 * pgd_offset does not require such a barrier.
248 */
249
250 /* Find an entry in the second-level page table.. */
pmd_offset(pud_t * dir,unsigned long address)251 extern inline pmd_t * pmd_offset(pud_t * dir, unsigned long address)
252 {
253 pmd_t *ret = pud_pgtable(*dir) + ((address >> PMD_SHIFT) & (PTRS_PER_PAGE - 1));
254 smp_rmb(); /* see above */
255 return ret;
256 }
257 #define pmd_offset pmd_offset
258
259 /* Find an entry in the third-level page table.. */
pte_offset_kernel(pmd_t * dir,unsigned long address)260 extern inline pte_t * pte_offset_kernel(pmd_t * dir, unsigned long address)
261 {
262 pte_t *ret = (pte_t *) pmd_page_vaddr(*dir)
263 + ((address >> PAGE_SHIFT) & (PTRS_PER_PAGE - 1));
264 smp_rmb(); /* see above */
265 return ret;
266 }
267 #define pte_offset_kernel pte_offset_kernel
268
269 extern pgd_t swapper_pg_dir[1024];
270
271 #ifdef CONFIG_COMPACTION
272 #define __HAVE_ARCH_PTEP_GET_AND_CLEAR
273
ptep_get_and_clear(struct mm_struct * mm,unsigned long address,pte_t * ptep)274 static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
275 unsigned long address,
276 pte_t *ptep)
277 {
278 pte_t pte = READ_ONCE(*ptep);
279
280 pte_clear(mm, address, ptep);
281 return pte;
282 }
283
284 #define __HAVE_ARCH_PTEP_CLEAR_FLUSH
285
ptep_clear_flush(struct vm_area_struct * vma,unsigned long addr,pte_t * ptep)286 static inline pte_t ptep_clear_flush(struct vm_area_struct *vma,
287 unsigned long addr, pte_t *ptep)
288 {
289 struct mm_struct *mm = vma->vm_mm;
290 pte_t pte = ptep_get_and_clear(mm, addr, ptep);
291
292 page_table_check_pte_clear(mm, addr, pte);
293 migrate_flush_tlb_page(vma, addr);
294 return pte;
295 }
296
297 #endif
298 /*
299 * The Alpha doesn't have any external MMU info: the kernel page
300 * tables contain all the necessary information.
301 */
update_mmu_cache(struct vm_area_struct * vma,unsigned long address,pte_t * ptep)302 extern inline void update_mmu_cache(struct vm_area_struct * vma,
303 unsigned long address, pte_t *ptep)
304 {
305 }
306
update_mmu_cache_range(struct vm_fault * vmf,struct vm_area_struct * vma,unsigned long address,pte_t * ptep,unsigned int nr)307 static inline void update_mmu_cache_range(struct vm_fault *vmf,
308 struct vm_area_struct *vma, unsigned long address,
309 pte_t *ptep, unsigned int nr)
310 {
311 }
312
313 /*
314 * Encode/decode swap entries and swap PTEs. Swap PTEs are all PTEs that
315 * are !pte_none() && !pte_present().
316 *
317 * Format of swap PTEs:
318 *
319 * 6 6 6 6 5 5 5 5 5 5 5 5 5 5 4 4 4 4 4 4 4 4 4 4 3 3 3 3 3 3 3 3
320 * 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2
321 * <------------------- offset ------------------> E <--- type -->
322 *
323 * 3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1
324 * 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
325 * <--------------------------- zeroes -------------------------->
326 *
327 * E is the exclusive marker that is not stored in swap entries.
328 */
mk_swap_pte(unsigned long type,unsigned long offset)329 extern inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
330 { pte_t pte; pte_val(pte) = ((type & 0x7f) << 32) | (offset << 40); return pte; }
331
332 #define __swp_type(x) (((x).val >> 32) & 0x7f)
333 #define __swp_offset(x) ((x).val >> 40)
334 #define __swp_entry(type, off) ((swp_entry_t) { pte_val(mk_swap_pte((type), (off))) })
335 #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
336 #define __swp_entry_to_pte(x) ((pte_t) { (x).val })
337
pte_swp_exclusive(pte_t pte)338 static inline bool pte_swp_exclusive(pte_t pte)
339 {
340 return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
341 }
342
pte_swp_mkexclusive(pte_t pte)343 static inline pte_t pte_swp_mkexclusive(pte_t pte)
344 {
345 pte_val(pte) |= _PAGE_SWP_EXCLUSIVE;
346 return pte;
347 }
348
pte_swp_clear_exclusive(pte_t pte)349 static inline pte_t pte_swp_clear_exclusive(pte_t pte)
350 {
351 pte_val(pte) &= ~_PAGE_SWP_EXCLUSIVE;
352 return pte;
353 }
354
355 #define pte_ERROR(e) \
356 printk("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e))
357 #define pmd_ERROR(e) \
358 printk("%s:%d: bad pmd %016lx.\n", __FILE__, __LINE__, pmd_val(e))
359 #define pgd_ERROR(e) \
360 printk("%s:%d: bad pgd %016lx.\n", __FILE__, __LINE__, pgd_val(e))
361
362 extern void paging_init(void);
363
364 /* We have our own get_unmapped_area */
365 #define HAVE_ARCH_UNMAPPED_AREA
366
367 #endif /* _ALPHA_PGTABLE_H */
368